The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, April 03, 2005

Spiders, One of Our Least Loved Animals by Ro Wauer

For much of my life I had a mild case of arachnophobia, a fear of spiders. But in about 1967 or '68, while I was working at Big Bend National Park, I spent a few days helping Dr. Willis Gertsch of the University of Arizona, collecting spiders. By the end of that experience my fear had turned to admiration and curiosity; I was even able to pick up a few (with forceps) to examine them more closely. Before that, my orientation about spiders probably evolved from the Mother Goose rhyme "Little Miss Muffet, Sat of a tuffet, Eating of curds and whey. There came a big spider, And sat down beside her, and frightened Miss Muffet away."

Recently, while browsing at the Victoria library, I discovered a fascinating little book by Paul Hillyard, "The Book of the Spider," that reminded me again of these truly fascinating creatures. The approximately 35,000 species of spiders in the world are related to scorpions, mites, ticks, and other arachnids; they are not insects. Spiders possess eight legs, two leg-like palps (mouthparts), and simple eyes, usually eight in number. They have limited vision, relying mainly on touch. The abdomen contains the vital organs, including silk glands. Spinning organs (two, four or six, depending on the species), from which strands of silk are issued through tiny "spigots," are located at the end of the abdomen.

Spider webs often are the most obvious evidence of spiders, although some species do not build webs. But most trail a dragline and secure it behind them. And many small spiders use long airborne threads to disperse. Webbing is also used to wrap up or "mummify" their prey, and some females wrap up the male after mating. And some crab spider males tie the female with silk, the "bridal veil," prior to mating. Spider webs can be amazingly strong and are often sticky. Our local garden spider's webbing is a good example.

Humans have learned to utilize spider webbing in a number of ways. Natives in New Guinea construct a six-foot circle of cane in which a spider spins its web within the circle. That webbing is so strong that it is used to catch fish up to one pound. The strong threads of garden spiders were once used as crosshairs in telescopes and other fine optical instruments. The U.S. Government currently is supporting genetic engineering for the use of spider webbing for bulletproof vests. Regular Kevlar material can stretch up to four percent before breaking, but spider silk will stretch as much as 15 percent before breaking. And in France and Spain, cobweb spiders are released in wine cellars to provide an authentic ambiance and also to control the insects that bore into corks. Other uses have included the use of spider webs as Band-Aids, medicines, and food.

A spider's life cycle ranges from one to two years, although female tarantulas and trap-door spiders can survive for up to twenty years. Most species can survive for long periods, even months, without eating, and many never touch standing drinking water. Spider diets can contain almost any kind of animal small enough to get caught in a web. Insects are most often captured, but larger species such as hummingbirds and lizards are occasionally taken as well. The body of the victim is punctured by the spider's fangs and either killed outright or paralyzed to preserve the prey until later. When eating, the spider's digestive juices liquefy the inside of its victim that is then sucked out by the stomach's pumping action. The remainder is often mashed up with the spider's strong jaws and eaten.

Spiders undoubtedly are tough and fascinating creatures. Remember the Mother Goose rhyme: "Incey Wincey spider Climbing up the spout; Down came the rain And washed the spider out; Out came the sunshine And dried up all the rain; Incey Wincey spider Climbing up again."